The Center for Astrophysics | Harvard & Smithsonian High Energy Astrophysics division focuses on X-ray astronomy and instrumentation involved in observations of high-energy sources. This research aims ...

Everything you’ve ever seen or experienced on Earth was once a nebulous collection of floating gas and dust. Science is starting to understand how those particles came to take the forms you recognize ...

Interstellar space — the region between stars inside a galaxy — is home to clouds of gas and dust. This interstellar medium contains primordial leftovers from the formation of the galaxy, detritus ...

About 13.8 billion years ago, the Big Bang gave rise to everything, everywhere, and everywhen—the entire known Universe. What caused the Big Bang? What happened that first moment at the beginning of ...

For the first 380,000 years or so after the Big Bang, the entire universe was a hot soup of particles and photons, too dense for light to travel very far. However, as the cosmos expanded, it cooled ...

Large galaxies like the Milky Way formed out of mergers with smaller galaxies and by stealing some of their stars. Astronomers discovered that as many as 25% of galaxies are currently merging with ...

Matter and energy are the two basic components of the entire Universe. An enormous challenge for scientists is that most of the matter in the Universe is invisible and the source of most of the energy ...

Black holes are some of the most fascinating and mind-bending objects in the cosmos. The very thing that characterizes a black hole also makes it hard to study: its intense gravity. All the mass in a ...

The Milky Way is our galactic home, part of the story of how we came to be. Astronomers have learned that it’s a large spiral galaxy, similar to many others, but also different in ways that reflect ...

Looking for hidden structures and unusual stars that reveal the Milky Way’s history. Since our galaxy grew by merging with and eating other galaxies, traces of that violent past are visible in the ...

Stars have a life cycle: they’re born, they pass through middle age, and they die. The birth of a star determines much of how it lives that life. For that reason, researchers study star-forming ...

Scientists now estimate that there are over a trillion galaxies in the Universe. Many follow broad classification patterns, but no two are exactly alike. The variety of galaxies we see gives us a ...